_url & QUERY_STRING for routing, why?

Why is Phalcon adding _url to QUERY_STRING and using it for routing as opposed to using REQUEST_URI and stripping query params from it?

If above is how routing is done when why is it not the behavior of Phalcon 2, should I report it as a bug?

I am also interested in knowing what else is being modified in global vars by Phalcon?

Scenario

I have setup Phalcon2, php56 (from remi) and nginx using php-fpm and first thing I noticed that none of the routes were working. After comparision of $_SERVER with phalcon 1.3.4 that I had running on another box, I found that Phalcon 1.3.4. modifies QUERY_STRING by adding _url which is then used for routing.

To demonstrate this consider the following urls and QUERY_STRING values: